From b01ed99a1cd0c863c8709930658513c04dd70f61 Mon Sep 17 00:00:00 2001
From: rtk0c <mail.tianyig@gmail.com>
Date: Thu, 30 Jun 2022 23:47:26 -0700
Subject: Rename Entrypoint/ to ImGuiBackend/ for accuracy

---
 app/source/Cplt/ImGuiBackend/Backend_OpenGL2.cpp | 106 +++++++++++++++++++++++
 1 file changed, 106 insertions(+)
 create mode 100644 app/source/Cplt/ImGuiBackend/Backend_OpenGL2.cpp

(limited to 'app/source/Cplt/ImGuiBackend/Backend_OpenGL2.cpp')

diff --git a/app/source/Cplt/ImGuiBackend/Backend_OpenGL2.cpp b/app/source/Cplt/ImGuiBackend/Backend_OpenGL2.cpp
new file mode 100644
index 0000000..943a527
--- /dev/null
+++ b/app/source/Cplt/ImGuiBackend/Backend_OpenGL2.cpp
@@ -0,0 +1,106 @@
+#include "Backend.hpp"
+
+#if BUILD_CORE_WITH_OPENGL2_BACKEND
+#	include <glad/glad.h>
+
+#	include <GLFW/glfw3.h>
+#	include <backend/imgui_impl_glfw.h>
+#	include <backend/imgui_impl_opengl2.h>
+#	include <imgui.h>
+#	include <stdexcept>
+#	include <iostream>
+
+#	define IMGUI_IMPL_OPENGL_LOADER_CUSTOM
+#	include <backend/imgui_impl_opengl2.cpp>
+
+class OpenGL2Backend : public RenderingBackend
+{
+private:
+	GLFWwindow* mWindow;
+
+public:
+	OpenGL2Backend()
+	{
+		glfwSetErrorCallback(&GlfwErrorCallback);
+		if (!glfwInit()) {
+			throw std::runtime_error("Failed to initialize GLFW.");
+		}
+
+		mWindow = glfwCreateWindow(1280, 720, "Cplt", nullptr, nullptr);
+		if (mWindow == nullptr) {
+			throw std::runtime_error("Failed to create GLFW window.");
+		}
+		glfwMakeContextCurrent(mWindow);
+		glfwSwapInterval(1); // Enable vsync
+
+		if (gladLoadGLLoader((GLADloadproc)glfwGetProcAddress) == 0) {
+			throw std::runtime_error("Failed to initialize OpenGL.");
+		}
+
+		IMGUI_CHECKVERSION();
+		ImGui::CreateContext();
+
+		ImGui_ImplGlfw_InitForOpenGL(mWindow, true);
+		ImGui_ImplOpenGL2_Init();
+	}
+
+	virtual ~OpenGL2Backend()
+	{
+		ImGui_ImplOpenGL2_Shutdown();
+		ImGui_ImplGlfw_Shutdown();
+		ImGui::DestroyContext();
+
+		glfwDestroyWindow(mWindow);
+		glfwTerminate();
+	}
+
+	virtual void RunUntilWindowClose(void (*windowContent)())
+	{
+		while (!glfwWindowShouldClose(mWindow)) {
+			glfwPollEvents();
+
+			ImGui_ImplOpenGL2_NewFrame();
+			ImGui_ImplGlfw_NewFrame();
+			ImGui::NewFrame();
+
+			windowContent();
+
+			int displayWidth, displayHeight;
+			glfwGetFramebufferSize(mWindow, &displayWidth, &displayHeight);
+			glViewport(0, 0, displayWidth, displayHeight);
+
+			const ImVec4 kClearColor = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
+			glClearColor(kClearColor.x * kClearColor.w, kClearColor.y * kClearColor.w, kClearColor.z * kClearColor.w, kClearColor.w);
+			glClear(GL_COLOR_BUFFER_BIT);
+
+			ImGui::Render();
+			ImGui_ImplOpenGL2_RenderDrawData(ImGui::GetDrawData());
+
+			glfwMakeContextCurrent(mWindow);
+			glfwSwapBuffers(mWindow);
+		}
+	}
+
+	static void GlfwErrorCallback(int errorCode, const char* message)
+	{
+		std::cerr << "GLFW Error " << errorCode << ": " << message << "\n";
+	}
+};
+
+std::unique_ptr<RenderingBackend> RenderingBackend::CreateOpenGL2Backend()
+{
+	try {
+		return std::make_unique<OpenGL2Backend>();
+	} catch (std::exception& e) {
+		return nullptr;
+	}
+}
+
+#else // ^^ BUILD_CORE_WITH_OPENGL2_BACKEND | !BUILD_CORE_WITH_OPENGL2_BACKEND vv
+
+std::unique_ptr<RenderingBackend> RenderingBackend::CreateOpenGL2Backend()
+{
+	return nullptr;
+}
+
+#endif
-- 
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